Hard point-contact spectroscopy and scanning probe microscopy/spectroscopy are powerful techniques for investigating materials with strong expandability. To support these studies, tips with various physical and chemical properties are required. To ensure the reproducibility of experimental results, the fabrication of tips should be standardized, and a controllable and convenient system should be set up. Here, a systematic methodology to fabricate various tips is proposed, involving electrochemical etching reactions. The reaction parameters fall into four categories solution, power supply, immersion depth, and interruption. An etching system was designed and built so that these parameters could be accurately controlled. With this system, etching parameters for copper, silver, gold, platinum/iridium alloy, tungsten, lead, niobium, iron, nickel, cobalt, and permalloy were explored and standardized. Among these tips, silver and niobium's new recipes were explored and standardized. Optical and scanning electron microscopies were performed to characterize the sharp needles. Relevant point-contact experiments were carried out with an etched silver tip to confirm the suitability of the fabricated tips.As diagnostic groups are increasingly called upon to participate in experimental campaigns at remote facilities, there is a need to develop portable versions of plasma diagnostic systems. One such diagnostic is laser induced fluorescence (LIF). Here, we describe a portable LIF apparatus that eliminates the need for an optical table, beam splitters, and an optical chopper. https://www.selleckchem.com/products/ecc5004-azd5004.html All of the light exiting the laser system is coupled through optical fibers to the experiment and housekeeping diagnostics. The collected light is coupled through an optical fiber as well. A key feature is modulation of the tapered amplifier current instead of physical modulation of the laser output. Using this portable LIF system, measurements of ion temperature, ion flow, and relative metastable ion density are reported for two different remote experiments.Precise characterization and tailoring of the spatial and temporal evolution of plasma density within plasma sources are critical for realizing high-quality accelerated beams in plasma wakefield accelerators. The simultaneous use of two independent diagnostics allowed the temporally and spatially resolved detection of plasma density with unprecedented sensitivity and enabled the characterization of the plasma temperature in discharge capillaries for times later than 0.5 ?s after the initiation of the discharge, at which point the plasma is at local thermodynamic equilibrium. A common-path two-color laser interferometer for obtaining the average plasma density with a sensitivity of 2 × 1015 cm-2 was developed together with a plasma emission spectrometer for analyzing spectral line broadening profiles with a resolution of 5 × 1015 cm-3. Both diagnostics show good agreement when applying the spectral line broadening analysis methodology of Gigosos and Cardeñoso in the temperature range of 0.5 eV-5.0 eV. For plasma with densities of 0.5-2.5 × 1017 cm-3, temperatures of 1 eV-7 eV were indirectly measured by combining the diagnostic information. Measured longitudinally resolved plasma density profiles exhibit a clear temporal evolution from an initial flat-top to a Gaussian-like shape in the first microseconds as material is ejected out from the capillary. These measurements pave the way for highly detailed parameter tuning in plasma sources for particle accelerators and beam optics.Spark gap switches are used in various high-power pulse systems because they can quickly transfer the energy stored in the capacitor to the load. A rotary trigger double spark gap (RTDSG) switch is proposed in this paper as a type of switch capable of high repetition at high power. It was found that a pulse switching of 20 kV and 1 kHz was possible by applying the multiple RTDSG switches to increase the repetition rate of the switch. In addition to the basic operating principle of the RTDSG, the effects of switching-related parameters on the operating frequency of the switch were analyzed. As an example of promising applications of the high repetition RTDSG, the generation of shock waves by underwater discharge and the effective dispersion of carbon nanotubes using the shock waves are reported.Wideband RF cavity beam position monitors (CBPM) have been increasingly employed for short bunch interval operations in several linear accelerators. At a few nanoseconds of bunch spacing, the loaded quality factor of the CBPM TM110 dipole eigenmode is required to be sufficiently low to minimize the signal interference between consecutive bunches. Moreover, the bunched beam also couples to several unwanted higher-order modes (HOM), such as the TM210 and TE111 eigenmodes, which also may result in an error of the bunch position measurement if no precautions are taken. In the fabrication phase of CBPMs, the mode coupling can alter the TM110 mode frequency and therefore causes an error in its tuning, e.g., 0.3% for a 4.875 GHz CBPM with QL = 22.5. This error needs to be identified so that the precise tuning is enabled since the dipole mode frequency becomes critical for the position evaluations as the signal processing is relatively phase-sensitive. This paper presents an approach to extract the pure unperturbed frequency of the dipole mode, not altered by the response to coupled HOMs. An analytic model based on the superposition law applied to electromagnetic fields has been developed to characterize the response of coupled HOMs in the S-parameter measurement. The model has been further verified with numerical simulation in the CST-Studio software by analyzing an approximate single-mode response CBPM. The correction method was applied on a wideband CBPM prototype for the pre-research plan of future high repetition rate hard XFEL at the Chinese Academy of Engineering Physics.We derived S-parameter based expressions for the intrinsic quality factor of an arbitrary coupled multiport microwave cavity and a non-ideal test fixture. Practical accuracy limitations of the obtained expressions specifically for superconducting accelerator cavities were evaluated both analytically and with the simulation software. The resulting formulas can be used to extract the intrinsic quality factor of normal-conducting and superconducting cavities directly from the calibrated S-parameter measurements.